If you're not getting your front high enough, lean back, push your heels forward and your toes back, that gives the back a little shunt forward and brings the front up. Once you've got manualling down you can use that to keep a slow manual going a bit further and giving you a bit of a boost. If your frames got a long back end manuals are an absolute b*****d (yet still entirely possible).. If your going of the back, weight to the front and feather, feather, the back brake and that should sort you out! Learning on a hill is always best, mess about with various gradients